Project Summary The long-term objective is to understand how visual performance varies across the visual field during childhood, adolescence and adulthood, and the neural correlates and possible oculomotor correlates underlying such changes. Vision at the center of gaze (fovea) has high sensitivity and resolution, facilitating good performance in many tasks, but performance decreases with increasing distance from fovea. Simple radial distance from fovea ?eccentricity? is not the only relevant retinotopic parameter for perception. At any given eccentricity stimuli can fall anywhere along circle, and the polar angle of a stimulus at ?isoeccentric? locations also has pronounced effects on perception in human adults, captured by a Performance Fields (PF) map. And yet the role of the polar angle has not been studied in children and adolescents, and the underlying neural representations and possible oculomotor correlates are practically unknown. PF present an opportunity for establishing tight quantitative links between behavior and neural representations of visual space. The proposed studies will measure PF in children, adolescents and adults, under different attentional states (Aim 1), along with fMRI visual field maps (Aim 2) and fixational oculomotor behavior (Aim 3). By highlighting and characterizing the functional, oculomotor and neural correlates of PF and their modulations across multiple timescales, the proposed studies will elucidate critical constraints on perception and performance as a function of polar angle. We will implement a computational observer model that is the glue that binds the three aims together. In addition to advancing our knowledge of visual perception, the proposed research will enable us to make predictions about human performance. The characterization of PF has significant implications for ergonomic and human factors applications, which should take into account functional plasticity during development, compensation via selective attention, and oculomotor behavior. For example, it is of critical importance for user-interfaces that present information at different locations of the visual field. With an understanding of how attention affects PF we can extend our knowledge to real-world displays, such as navigation and cockpit alerting systems, control panel layouts in cars, computer-aided detection systems, and software for presenting radiological images. Furthermore, the gained knowledge can aid the design of artificial image recognition systems. This research will inform the development of compensatory strategies and interventions to deal more effectively with the limitations of the visual system. In addition, understanding the functional causes of performance differences across the visual field and how attention and/or oculomotor behavior interact with them will improve our models of visual dysfunction (e.g., macular degeneration, retinitis pigmentosa), as well as the diagnosis of these disorders.